Effective diversion of acid is important for efficient treatment of, among other things, carbonate reservoirs. It also increases the depth of penetration of acid into the reservoir. The use of viscoelastic surfactants (VES) based fluids in acid diversion treatment is becoming prevalent due to their non-damaging nature. These fluids develop viscosity by aggregation of surfactants molecules to form micelles. These VES fluids break down easily on dilution or on contact with oil thereby leaving negligible residue in the reservoir.
One drawback of VES fluids is their general incompatibility with corrosion inhibitors. In some instances, corrosion inhibitors interfere in the aggregation of the surfactant molecules in VES fluids and affect at least the gelling properties of VES. Since, rate of corrosion increases at higher temperature, the use of corrosion inhibitors are inevitable in gelled acids for higher temperature applications. There is therefore a need for VES that may be used in the presence of corrosion inhibitors or are corrosion inhibitors themselves.